Set Information

Story-line

Aether Revolt (AER), the second set and smaller set of the Kaladesh block, will be released January 20, 2017. Aether Revolt will contain 184 different cards and be the 73nd Magic Expansion overall. The expansion symbol will be reminiscent of a flower, similar to the Kaladesh symbol. As we learned in Magic Origins Kaladesh is the birthplane of the famous planeswalker Chandra Nalaar. In the first set of the block we learned about Kaladesh, which was in the throes of an inventors' renaissance. The governing Consulate had fostered innovation and optimism for decades. But then, at the pinnacle of this era of creativity, the Consulate started confiscating inventions and detaining many genius inventors.
The Consulate claimed that their actions were for the safety of the citizens, but it has become apparent that the Planeswalker Tezzeret looms behind the aggression. This sets the stage for Aether Revolt the second set of the block. We saw the amount of havoc Chandra was able to cause on this plane, where Fire Magic is strictly banned, already as a teenager. It wasn't hard to imagine her coming back to Kaladesh to lead a revolt against the Consuls, who hunted and tortured her as a kid. Chandra has returned to her former home backed by a powerful team of planeswalkers to stop Tezzeret's plans. We know the slogan of the set: “It's Time to Take the Power Back”, but that could also be quoting someone else, like Saheeli Rai, Rashmi or even Tezzeret. Who will triumph in this conflict and what will be left of the once blossoming and beautiful Kaladesh afterwards?

Mechanics

Let's take a look at the new and recurring mechanics of the set. Energy and Vehicles, first seen on Kaladesh cards, are still around although they are used for more aggressive purposes now. The Consulate is restricting the citizens' access to all kinds of resources, causing inventors to Improvise and Revolt. Here is how that translates to gameplay on the new cards:

Energy

Let's start with the magical substance that can be found throughout the multiverse indeed, but which became a formative part of the entire ecosystem only on Kaladesh. Technically purified aether is the power source for the overall progress on Kaladesh. In the game this is represented by energy counters, which are a new type of counters a player can obtain. There are several cards that provide energy counters, and other cards using these energy counters to create great effects. Many cards can even do both. The big difference to conventional Mana is that energy counters do not expire. Players can therefore accumulate them in the long term for a massive project in the future, or use them for many small advantages in the present. Energy thus provides a new strategic challenge in the form of this unusual resource management.

Vehicles

Vehicles are no new mechanic at all, they are a new subtype of artifacts, with a completely new card frame design! Heart of Kiran and many other vehicles represent an important part of the wondrous inventions, for which Kaladesh is known. They usually start as lifeless artifacts until you use a special effect or one (or more) creatures in order to "crew" them.
Each vehicle uses the keyword Crew, followed by a number. This number represents the combined strength that the creatures must have at least, which you are tapping for the vehicle to be transformed into a creature until end of turn. Between flying airships, Dreadnoughts, and Colossi Kaladesh offers the right vehicle for every occasion – even oppression and revolution.

Revolt

People don't revolt while everything is working well for them, like it had been on Kaladesh for decades. Times have changed though. Now that people see their ingenuity, their hard work, and their loved ones disappear under the oppression of the Consulate, they are ready for more desperate measures than ever before. Revolt is a new ability that depends on a permanent you control leaving the battlefield. Revolt can appear as a bonus on an instant or sorcery spell, or creatures can have Revolt abilities which let them enter the battlefield with +1/+1 counters or produce different effects when they enter the battlefield.
Revolt abilities check the current turn for a permanent leaving the battlefield while under your control. It doesn't matter where that permanent went or who owned it in the first place. The people of Kaladesh are not picky anymore. They are instantly ready to revolt once they lose just one more thing to the consulate oppression. Did a creature die while under your control, or was an enchantment returned to your hand, or did you sacrifice a Clue token or a fetchland? It doesn't matter, Kaladesh's population will respond with a Revolt to almost anything!

Improvise

For the inventors this means life is no longer about inventing as an art form. Instead of following their heart and building whatever they fancy, life is now about cobbling together the tools for a revolution. Inconveniently, that task is even harder now that the consulate has been rationing resources. Our beloved inventors can't be stopped that easily though – they just started to Improvise!
Spells with the new ability Improvise let you use your artifacts to help cast them. You can tap an artifact as you cast the spell like you would tap a land, paying for one of the required generic mana.
Improvise won't ever cover the colored mana portion of a mana cost, but if you use Improvise to cast a spell that costs only generic mana you may be able to eliminate the need for mana altogether, as you can tap any number of artifacts to reduce the cost further and further.
Technically, tapping your artifacts for improvise happens after you activate mana abilities. That means if you tap an artifact for mana, it will already be tapped when it comes time to Improvise, so you can't do both. Ideal material for Improvise includes summoning sick artifact creatures, new vehicles or equipment, which will still be active after getting tapped.
So grab your tools, get ready to improvise, and join the rebel alliance with your new Aether Revolt cards!